Engine break in
 

So I just finished rebuilding a 13b. Everything works and it runs great. Didn't do a comp test yet but it starts up right away and pulls strong. My concern, it's been 250 miles and I see very faint blue smoke, it doesn't smoke bad and it's barely noticeable but it's there. I know it's oil cause I am premixing and had to add oil already. I think I made a mistake by using synthetic oil and the oil control rings are having a hard time seating/lapping properly. Can I still save it if I put in conventional oil later today? Opinions?

Also, I'm running1/2 oz per gallon on the premix so I'm pretty sure it's not that.

Irons were lapped and the oil rings and springs are all brand new. It just seems like a little bit of oil is getting by. The smoke is only noticeable in certain light.

That is why it smokes.

Hmm? Please explain. Should I even bother changing the oil? It's got Mobil 1, 10w30 full synthetic in it atm.

From what I gather is it because the irons and the rings still need to lap and conform to eachother? And that's why it's burning oil? Sorry for the noob inquiries. It's my first rebuild.

You shouldn't have had it lapped. Rookie mistake. When Mazda started the nitriding process for the 79-80 model year, it rendered lapping obsolete. The problem is once you lap a modern nitrided iron, it removes the hardened layer and all that's left underneath is far softer than even the 78 and older irons, which could actually be lapped several times before they became too thin to reuse. And yes those earlier engines would start to smoke pretty soon before 100k miles was reached. It was due to the oil seals wearing out.

You engine has several things wrong with it. For one thing the irons are lapped. Lapped irons = junk. They ruin all the seals on the sides of the rotors. Problem 2 = you used synthetic oil in a fresh rebuild. This prevents things from seating or bedding in properly. Problem 3 = the seal springs are probably stock duty. I've had better luck with the competition outer springs you can get from Mazdatrix.

For example I have a very smokeless fresh rebuild I just test drove for the first time today. You can search for the Icy build. Anyway it doesn't smoke. It has intact nitriding on the irons, along with comp outer springs, plus good used oil seals (no need for new ones as the wear was minimal), and new Atkins Viton o-ring inserts.

I think it has about 10 miles on it. No smoke.

Ouch... that really hurts.

My irons are from a 12 a with no injector ports. The center iron has tall primaries. I might be mistaken but I believe they are pre 79. I'm going to drain the synthetic oil and throw some conventional in there tomorrow morning. And yes, I did use regular springs on the oil rings with Mazda seals. I opted for those cause I wasn't sure if the vitons were a good choice.

I really hope i can save it and stop the smoking and try to get at least 100k but it's not looking so well right now. Im even considering lucas plus castrol gtx but i know thats just a band aid.

Like I said it's barely visible, for a minute I also assumed it was because of the afr. It's running a 48ida super rich at idle. Like 11 a/f in the idle circuit then 13.5 to 12.5 at wot. I did the whole rev the engine to 4k and let go test, not any visible smoke. U can only see it against something dark or if u shine a flashlight over the tailpipe. I read somewhere on the aus forums that u can get a very light blue smoke from running really rich since the oil doesn't burn off completely. I guess it's just me hoping were wrong but I doubt it...

i've never used competition oil springs, and no trouble here, in fact using a stiffer than stock spring on a softer than stock iron, might be bad.

second, if its too rich (or too lean) it'll smoke, so lean it out. too rich also dilutes the oil, so its double bad.

i'd also ditch the synthetic, its bad for break in

Well, there's still hope. I just got a jug of gtx and a k&n filter. It's only got 250 miles on the motor so I hope I can still bed those rings properly. Compression seems to be fine so I hope it's just the oil and the richness. I'll post developments here.

This is the first I hear not to lap the irons. That's not good news for my rebuild then. My irons had a very small step that you could barely catch with your nail so I decided to get them lapped. Would something so small would have been ok for a fresh rebuild? I thought since it's apart might as well lap them and get that step removed. Are my irons junk then?

So after countless hours of research and carefully examining my engine assembly pictures I spotted a flaw and i proceeded to punch myself in the face. I overlooked the importance of installing the oil control spring in the correct direction relative to the direction the rotor spins. All 4 inner control ring springs are backwards, so as my engine runs the control rings spin in their grooves preventing them from bedding in properly. Its actually surprising how little it smokes in this condition. Ill be pulling the engine soon and will replace all the control ring inserts and springs. Thanks guys for the input, this is my very first engine build and turns out it was just a rookie mistake on my part, ill never do that again...